Ohio State junior defensive end Nick Bosa, one of the top NFL draft prospects in the nation, underwent surgery for a "core muscle injury" this week and does not have a timetable for a return, coach Urban Meyer said Thursday.

Meyer announced the news on his weekly radio show on 97.1 The Fan in Columbus.

Bosa sustained the injury in the third quarter of last week's game against TCU. Meyer on Monday described the injury as a "groin and abdominal issue."

It was known early in the week that Bosa would not play in Saturday's home game against Tulane.

"We hope to get him back as soon as possible. We're not sure when that will be," Meyer said on radio, according to Cleveland.com. "A lot of it is the recovery. He's obviously one of the best players in football, but even a better person from an incredible family. So prayers, hug him up, and let's go."

The surgery makes it unlikely Bosa would be available for a Sept. 29 game at Penn State. Other key games in the Big Ten East come in the final month -- Michigan State (Nov. 10) and Michigan (Nov. 24).